A Blockchain-Based Location Privacy-Preserving Scheme in Location-Based Service

Algorithm 1

Collaboration based on private chains.

Input:

  R (The request areas), n (number of collaborative users),

  N (Minimum private chain length);

Output:

  The set of collaborative users in private chain Setcoll;

     1:  The request user (private chain initiator) published the request

  areas R, the value of incentive and the number of

  collaborative users n in the public chain;

     2:  Users whose assistance area R meet the requirements and

  willing to participate in the collaboratives users Setcu;

     3:  for Each u in Setcu do

     4:      Check users assistance locations locu of u;

     5:      iflocu do not match user’s need then

     6:        Turn back to 3;

     7:      else

     8:        Put u into the set Setcoll;

     9:      end if

     10: end for

     11: if Len (Setcoll) >N then

     12:     Establishes the private chain with these collaborative

    users;

     13: else

     14:     Publishing the request another times;

     15: end if

     16: return Setcoll;